At present, coal is still the main fuel in the power industry. With the social development and economic improvement, there is a sharp increase of demand of electric power, and a sharp decrease of coal storage, and also huge damage to our environment.
However, biomass is a renewable energy containing carbon. It is the characteristics of carbon neutral make biomass energy be applied for replacing part of fossil energy represented by coal, and reducing emission of carbon dioxide to mitigate greenhouse effect.
Biomass and coal co-fired is an excellent method for biomass energy large-scale utilization. It is an efficient and environmental method for producing energy, which can not only decrease the emission of pollution and carbon dioxide, but also utilize the biomass fuel with low heat value efficiently.
Radiocarbon (14C) is a radioactive isotope of carbon, which was first discovered by Martin Kamen and Sam Ruben at the Radiation Laboratory of UC Berkeley in Feb. 27, 1940.
The cosmic rays hitting nitrogen atoms in the atmosphere make the 14C production. The living creatures' 14C radioactivity is consistent with the atmosphere level, because of the atmosphere carbon cycle. However, the coal's 14C radioactivity decays mostly, because of being buried deep in the ground for millions of years. So, the power station burn the biomass or not, and how much their burned, in other words, how is the blending ratio could be known by sampling the flue gas in the boiler flue of coal and biomass co-fired power station and measuring the 14C in the carbon dioxide.
The biomass blending rate detection technology, this invention involves, is based on the radiometric dating of 14C isotopes. This technique was first applied for research of archaeology and geology. Nowadays, it is also applied for identification of biological base materials and detection of bio fuel rate in the garbage incineration power station as an effective method for biological component identification.
Differ from the situation of garbage incineration power station, the supply of bio fuel is affected by season, which make the biomass blending rate is no more than 5% in the coal and biomass co-fired power station. While the biomass blending rate is low, accelerator mass spectrometry (AMS) is the most accurate detection method for 14C radioactivity, but the equipment is too expensive to be popularized.
Lacking of effective and reliable detection technology and device of biomass blending rate make it unable that the government formulate standards and policies for coal and biomass co-fired power generation subsidies, which limits the development of co-fired power generation technology and its market development.